remove redundant '/manga' prefix from paths

We needed the prefix to distinguish anime paths from manga paths,
now that anime is no more, the redundancy shall be purged.

src/screens/manga/Browse.tsx

@@ -0,0 +1,12 @@
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+import React, { useContext, useEffect, useState } from 'react';
+
+export default function Browse() {
+    return <h1>fek</h1>;
+}